Circuit Arrangement for Limiting the White Level in Television Signals, More Particularly in Colour Television Signals

摘要

1,191,096. Television. INTERNATIONAL STANDARD ELECTRIC CORP. 12 Feb., 1969 [15 Feb., 1968], No. 7657/69. Heading H4F. Frequency-dependent limitation of the white level of a television signal is effected by dividing into two parallel paths I and II, the signal at the output of transistor amplifier T 1 , the signal having been clamped CN to synchronizing base or black level, path I including a compensating network W 1 /C 1 /L 1 which acts as a low-pass filter and removes frequencies above 0À5 Mc/s., in particular the colour sub-carrier 4À43 Mc/s., and a base clipper T 3 /T 4 which amplifies the excess white portion of the signal, the resulting white portion being added T 5 /T 6 to the original signal in channel II in phase opposition so that the original signal with its white level limited appears at output load resistor W 4 .